Small caps of IBB underperform
In the small-cap segment by market cap (capitalization), the top ten small-cap stocks from the SPDR S&P Biotech ETF (XBI) outperformed the top ten small-cap stocks from the iShares Nasdaq Biotechnology ETF (IBB) for August 25–31.
XBI’s top ten small-cap stocks returned 11.37%, while IBB’s top ten small-cap stocks gained 10.74%. Thus, IBB’s small-cap stocks underperformed.
The above chart reflects the performance of the top ten small-cap stocks for IBB and XBI.
Ariad and Prothena lead small-cap stocks
Ariad Pharmaceuticals (ARIA) stock rose 46.58% on news that Baxalta (BXLT) is in talks to acquire ARIA. ARIA has a weight of 0.24%. It closed at $9.44 on August 31, 2015. BXLT recently rejected a $30 billion offer from Shire (SHPG).
Prothena (PRTA) has a weight of 1.39% in XBI and 0.18% in IBB. PRTA closed at $57.83 on August 31. The stock bounced back from the oversold position and rose 16.98% for August 25–31. However, the stock on August 31 was still trading below its 50-day and 20-day moving averages.
Tetraphase Pharmaceuticals (TTPH) rose 13.37%. According to a company press release, Tetraphase will present 11 data presentations on the company’s lead drug, eravacycline, along with its pre-clinical pipeline program for TP-271 at the Interscience Conference of Antimicrobial Agents and Chemotherapy (or ICAAC) and the International Congress of Chemotherapy and Infection (or ICC). TTPH has a weight of 0.22%.